There are many types of fasteners such as buckles. They take various shapes and forms and one of the main features desired in most fasteners is the possibility of a quick release. However, very often this feature will cause accidental unwanted release of the connected parts on account of important forces which may be exerted on the devices. One application of buckles for which a quick release is not wanted is that when used with saftey and rescue vests, particularly those which are worn by persons working on scaffolds or high-rise construction buildings and where the vest is hooked to a connecting cable which, in turn, is anchored to some safe attachment points on the building. An important impact is suffered by the buckle and strap arrangement when an accidental fall by the worker is abruptly stopped due to the cable connection. One example of a vest using a strap and buckle arrangement of the type described may be found in applicant's copending patent application filed concurrently herewith. With the vest described in this co-pending application, it is extremely important that the buckle construction be tightly secured and safe since the buckle components must remain constantly attached together while the user is working as well as when a fall occurs.